1. Field of the Invention
The present invention relates to a flow measuring device that includes a adjusting terminal for adjusting an electronic circuit that controls input/output of a flow rate sensor.
2. Description of Related Art
A flow measuring device is for measuring the amount of suction air in an engine for an automobile, for example. The flow measuring device includes a flow rate sensor that is disposed in a flow passage to serve as a detecting part for detecting a flow rate, an electronic circuit that controls input/output of the flow rate sensor, and a connector that connects the electronic circuit to an external device. A terminal that electrically connects the electronic circuit and the external device, and an adjusting terminal for adjusting the electronic circuit are connected to the electronic circuit. The terminal and the adjusting terminal are held by a cylindrical connector housing having a bottom.
In a flow measuring device 100 (see FIG. 4A) disclosed in Japanese Patent No. 3323745, for example, a detecting part 101 (detecting element) that is disposed in a flow passage, and an electronic circuit 102 that is electrically connected to the detecting element and a connector 103 are provided. In the connector 103, one end of a terminal 105 projects from a bottom face 107 of a connector housing 106 toward an opening 108. A hole 110 that is recessed from the bottom face 107 further in the opposite direction from the opening is formed on the bottom face 107 of the connector housing 106. A adjusting terminal 111 is provided in the hole 110 to be exposed to the inside of the hole 110.
However, in this flow measuring device 100, since the adjusting terminal 111 is provided in the hole 110 on the bottom face 107 of the connector housing 106, if a water content enters into the connector housing 106 at the time of fitting a counterpart connector into the connector 103, water accumulates in the hole 110, and the water enters toward the electronic circuit from an interface 112 between the connector housing 106 and the adjusting terminal 111, so that an electrical defect may be caused. This phenomenon may be produced markedly particularly when the flow measuring device 100 is disposed such that the opening 108 of the connector housing 106 faces in the upper direction and the bottom face 107 faces in the lower direction.
A technology for adjusting an electronic circuit 201 is described (see FIG. 4B) in Japanese Patent No. 4170095. In a flow measuring device 200 described in Japanese Patent No. 4170095, a housing 202 that accommodates the electronic circuit 201, and a connector housing 203 are integrally formed; a part of a terminal 204 connected to the electronic circuit 201 is exposed to the outside of the housing 202; and a device 206 for adjustment is connected to this exposed portion (exposed part 205), so as to adjust the electronic circuit 201. However, this technology creates a need to seal the exposed part 205 after adjustment because the exposed part 205 used for adjustment is located to be in contact with outside air.
On the other hand, in the case of providing the adjusting terminal 111 in the connector housing 106 as in Japanese Patent No. 3323745, the adjusting terminal 111 is not in contact with outside air because of the fitting to the counterpart connector. Therefore, the adjusting terminal 111 does not need to be sealed after adjustment. Nevertheless, as described above, in the flow measuring device 100 in Japanese Patent No. 3323745, there is a problem that water easily enters toward the electronic circuit from the interface 112 of the connector housing 106 and the adjusting terminal 111.